A simple, rapid and sensitive spectrophotometric procedure for the determination of platinum has been elaborated. Pt traces were determined in the form of the PtCl(6)(2-) complex in hydrochloric acid solution whose concentration varies from 0.01 to 2 mol L(-1) by measuring the absorbance at 260 nm. The detection limit is 4.7 x 10(-7) mol L(-1), the linearity range from 2 x 10(-6) mol L(-1) to 7 x 10(-6) mol L(-1), and the correlation coefficient is r=0.9990. No significant interferences were observed from a majority of the investigated ions, such as Zn(II), Pb(II), Mn(II), Cd(II), Co(II) and Ni(II) with the exception of Cu(II), Sb(III), Fe(III), Pd(II), Sn(II) and I(-) ions. The method was successfully applied for the determination of Pt traces in different solid samples and the recovery from inorganic materials was studied.

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The adsorptive behavior of Pd" ions in the presence of dimethylglyoxime (DMG) was investigated using voltammetric techniques. It was found that the bis-dimethylglyoximato palladium(ii) complex is adsorbed strongly between pH 3 and 5 and between the potentials 0 and -0.3 V (vs. Ag/AgCl). The peak current is proportional to the Pd-DMG surface concentration, and increases linearly with scan rate (Blog i,,/L?u = 0.97). The adsorptive stripping response was evaluated with respect to pH, the concentration of the electrolyte, the addition of surfactants and the preconcentration potential. From the results a general scheme for the reduction process is given.

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The electrochemical behavior of Pt(IV) ions in the presence of dimethylglyoxime has been investigated using adsorptive stripping voltammetric method. The results indicated that the platinum is reduced from its adsorbed state as bis-dimethylglyoxi-mate platinum(IV) complex. The peak current is linearly proportional to the Pt(IV) concentration in the solution, thus representing the basis for a quantitative analysis. Various experimental parameters affecting the stripping response, indicating pH, the ligand concentration or the accumulation time and potential, and the scan rate, were studied to obtain a highly linear response. From the results the scheme for the reduction process of the platinum dimethylglyoximate complex in acidic media is presented.